List of free API-test stuff for developerππ½
If you're looking for all programming tools around API-test (not just free). Check this page List of API-test Programming Tools

ReqBin
ReqBin is the world's most popular online API testing tool for REST, SOAP and HTTP APIs. Test your APIs right from your browser. No coding. No desktop app. See why 850'000 of users use ReqBin for testing their APIs online!
Tag: API-test